1. Technical Field
The present invention relates to a recording apparatus such as an ink jet printer and to a method for recording a correction pattern.
2. Related Art
In the related art, an ink jet printer (hereinafter referred to as a “printer”) is widely known as a recording apparatus that performs recording onto a sheet transported by a sheet transporting device (hereinafter referred to as a “transporting device”, simply). In the transporting device in the printer, a sheet is intermittently transported at a predetermined transport rate by controlling the amount of rotation of a transport roller based on the detection result of a rotary encoder disposed coaxially with the transport roller which rotates to transport the sheet in a sub-scanning direction (transport direction).
Meanwhile, the printers individually have individual differences in a transport rate of a sheet transported by the rotation of the transport roller due to an error in alignment or the like therein. Furthermore, in the case where the rotational center of a disk-shaped, scaled encoder scale in the rotary encoder is misaligned with the center of the disk-shaped encoder scale, such individual differences in the transport rate of the sheet in every printer may appear as different detection results depending on a position at which the scale has been detected (transport rate error).
Accordingly, in a printer in JP-A-2007-261262, two positions displaced from each other by 180 degrees in a circumferential direction of a disk-shaped encoder scale are determined to individually measure transport rates of a sheet on the basis of the two positions, and then each transport rate measured at the two positions is averaged to estimate the transport rate of the sheet during a single rotation of a transport roller. Then, correction to reduce variation in the transport rate of the sheet, which results from the individual differences in each printer, is performed on the basis of the transport rate of the sheet which has been estimated in this manner.
Unfortunately, in the printer disclosed in JP-A 2007-261262, a transport rate of a sheet is calculated at a plurality of positions (for example, two positions) in the circumferential direction of the encoder scale, and significantly many processes must be performed to obtain the individual differences in the transport rate of the sheet in every printer.